op: I'm waiting for you gear heads and electricians to chime in. Simple was bringing 2 sets of batts and change them out when went dead very simple now had to go and get all technical lol

 

lol My thought is on nights when I want to run lights and troll banks I would toss the little DC genny in the boat. on normal nights when I am chasing bigheads I will just run my troller on 2 batterys .. it lasts all night. for me a little genny like this would save a TON of money and weight on my 1448. you can build the whole thing for around $200 and it weighs about 35 -40 lbs. The 3.5 predator motor is more than enough to run it.

 

Off the subject but is that like a 1.5" aluminum plate that's on?

 

i have only used small engines for go carts, air compressors, pumps and a few other items, all of those were really loud! is there something that can be done to quite them down? i dont know if its exhaust noise, crankcase noise or a lot of both? or maybe just the RPMs and engine load?

 

It's not the exhaust. It's the moving internal parts of the engine an a lil bit of exhaust noise. The reason the super quiet Honda EU generators cost so much is bc its a precision made motor with tight tolerances and a better muffler. Mexican kids can slap an air compressor motor together quik, not the case with the quiet 1s

 

I have 2 yamaha inverters, which are awesome, but I will define try be building one of these now that I'm running everything off DC power.

 

I have looked into this more than once. For a 12 volt system the pros out weight the cons. In fact only con to me is noise. It's cheap, simple, lite and serves an exact purpose. There are a bunch of "green" web sites where folks are using windmills to spin alternators for power supplies. They can tell you which brand produces the most juice with the lowest Rpms and they have good stats on alternators in general. Lower Rpms should equal a quiter motor. Plus there is always a genny box.

 

true. that's my line of thought also. it doesn't take much hp to turn alt. im thinking a idol 3.5 hp motor can make enough hp to turn a alt 2000 rpm. exhaust can be modified and redirected if need be.

 

Hf web site says max rpm is 3600. I can see 2000rpm at idle. You can oversize the alt. pully and play with gear ration to get max output or oversize your alt. to produce more power at idle. This is very doable!

 

How about this guys , liking the idea

But if search it I also found 24v alternators in as high as 150amp,WWR add a belt/pulley to fan reduction and add in a 24v alternator. We actually have the fan boat gears turning in our head on a new build and that new shop we have planned just might get 12 foot high doors.


Or this

 

Very interesting Garp... I definitely see far more benefits even with a 12 volt alternator than cons. its not a set up that everyone can use but will work in several applications.

 

So yall are wanting to charge batteries with an alternator like a truck?

 

Yep... cheaper and lighter than a standard generator and its 12 volt so no need for converters.

 

I don't remeber y but I was looking up high output alternators one time and they have some that put out ridiculous amouts at almost any rpm. Like starts charging full power at a few 100 rpm. They wer pricey tho

 

I'd say go for it. That's no different than what I run on my airboat. I got a 140 amp alternator (while running above 1200 rpm and 80 amp at idle) running 10-50w, 2- 30w and 2-10w floods at the same time. But that little engine will stay at wot all the time so that shouldn't matter. All off of one battery also. I wouldn't see a need of 2 batteries personally.

 

I'd say go for it. That's no different than what I run on my airboat. I got a 140 amp alternator (while running above 1000 rpm and 80 amp at idle) running 10-50w, 2- 30w and 2-10w floods at the same time. But that little engine will stay at wot all the time so that shouldn't matter. All off of one battery also. I wouldn't see a need of 2 batteries personally.

I am run a 24 volt troller, so I will need 2 batteries. With a big pully on the motor and the smallest I can on the alternator I should be able to keep the amps up at lower speed even on that small motor. I want to run my troller and 6 50w leds on the Funky Chipmunk. I think this will do it pretty easy with a 100 amp alt.

 

Also I got a after market alternator pulley. It's a smaller diameter so it will be spinning at a higher rpm at idle, keeping a better charge.

 

The more I think about your dc charger, the more I like the idea. I'm betting guys with fans could fix both the homemade generator and their fan up for quick disconnect and installation of a single alternator so it can be swapped between the two cause the good ones ain't cheap! No buying converters..no buying 2 to 3 grand of inverter generator/s...and a single charging system with its peripheral components such as switches, isolators, meters, etc. within the boat. Nice!

 

That's been done before and don't work as well as you would think. 1 downfall is just safety. They belt would literally ride next to the prop. If it jumps u just bought a new prop and who knows what else. 2, it just robs to much hp from the fan and changes everything as far as the fan performance.
You see a lot of floundering rigs setup like that though. Usually they have no shroud.

 

Should be. good thinking Skippy

 

 

i was looking at the Honda GC series motors, you can get a 5hp for under $300, its a belt drive overhead cam engine which should make it a lot quieter i would think, they say residential motor so maybe pretty quiet , they also have fuel pump instead of gravity fed so you could use boat fuel tank, or at least a remote tank that u can fill without the risk of spilling on the hot engine, and it looks like it has a decent muffler

 

 

Couldn't you fab a metal shroud to enclose the belt and pulley and keep it out of fan blade ???

 

This is the new shroud and fan set up with reduction on the motor, he moved the alt. to the front.

 

found a company that makes gas powered DC chargers, ALTEN, they have videos on Youtube, damn expensive but something to look at as far as HP vs output, looks like they coupled alternators directly to the engine

 

Checked them out.. good info crazy price!

 

10-4 Skippy. Havent seen that yet

 

I have been told (this isn't proven) that an alt. puts out around 25% of rated amps at idle. A 200 amp alt should put out 50amps at idle. However there is no reason mulitpal alts. Couldn't be used if needed.

 

Thats why we put the volt meter on the alt. and the different size pullys will change how fast the alt. spins at idle. so that is pretty much not going to be something to go by. to many variables in this set up. the best way for me to test this thing is going to be to buy a small engine and get to work making one. :tu:

 

I like that alternator mounted to the opposite end of the shaft. Makes a lot of sense.

 

I like what y'all are doing!